This week, SI.com is previewing all 30 MLB teams, counting down to the No. 1 team in the league. At No. 29: the Arizona Diamondbacks.

2014 Record and Finish: 64–98 (.395), fifth place in NL West (30th overall)

2015 Projected Record and Finish: 65–97 (.401), fifth place in NL West (29th overall)

The Case For

Getting full, healthy seasons from first baseman Paul Goldschmidt and outfielder A.J. Pollock is a reasonable expectation. Finding the fountain of youth for second baseman Aaron Hill isn’t. Arizona also needs the best-case scenario for Cuban import Yasmany Tomas, which means big power production at the plate, be it as a third baseman (unlikely) or rightfielder. Those are the bare minimum requirements for optimism regarding the Diamondbacks.

Beyond that, Arizona needs Patrick Corbin to return from Tommy John rehab on schedule and make a big impact in the second half, plus a similar contribution from top prospect Archie Bradley. The D-backs also must get a strong season from whoever plays where Tomas doesn’t, be it rookie Jake Lamb at third base or sophomore David Peralta in rightfield. A midseason, if not early-season, trade for a legitimate everyday catcher would also be good. Combine all of that with a little hocus pocus from new manager Chip Hale, and you might be able to squint and see Arizona as a possible wild-card contender. Maybe.

The Case Against

The Diamondbacks had the worst record in baseball last year, and it’s not clear that they made themselves any better over the offseason. Trading Miguel Montero may have made sense in terms of ridding themselves of a bad contract, but they failed to replace him and are now entering the season with Tuffy Gosewisch, a 31-year-old who has merited just 179 major league plate appearances to this point and posted a 41 OPS+ in those opportunities, as their starting catcher. Tomas was the team’s most significant addition, but he may prove to be the second coming of Mark Trumbo: a one-tool player who undermines his considerable power with a terrible plate approach and a lack of ability in the field.

Speaking of Trumbo, having him healthy may actually be a hindrance to this team given his sub-.300 on-base percentages and brutal play at both first base and leftfield, particularly if Tomas is the team’s other outfielder. Peralta and Ender Inciarte both played well enough as rookies last year to deserve starting jobs in the outfield, but could wind up blocked by Trumbo and Tomas.

The rotation is a conglomeration of back-end options. Swing-man Josh Collmenter, who pitched exclusively in relief two years ago, struck out just 5.8 men per nine innings last year and didn’t throw a single pitch that reached 90 mph over the final three months of last season. Despite all of that, he's getting the Opening Day nod. The big additions are Jeremy Hellickson, who is leaving pitching-friendly Tropicana Field for hitting-friendly Chase Field, and Rubby De La Rosa, who looks like a significant downgrade from the man he was traded from Boston for, Wade Miley. The bullpen is no more impressive. This team will likely have a hard time reacing 75 wins.

It’s unclear how steep Tomas’s learning curve is going to be on either side of the ball or how quickly he’ll traverse it, if at all, but what he does could have far-ranging impacts for Arizona. For example, if Tomas sticks at third base, Lamb and Brandon Drury—the organization’s top two hitting prospects—need to find another position. If Tomas moves to the outfield, Peralta and Inciarte are going to wind up on the bench. Early reports are that Tomas is a disaster at the hot corner, but he was practically starting from scratch at the position this spring, and at 24, he’s young enough to be taught new tricks. Then again, he wasn’t highly regarded in the outfield, either, and at 6'2", 230 pounds is something of a bad-body player with a physique built for power but not necessarily athleticism.

Will Tomas be a detriment to team defense at either position? Will he be the force in the middle of the lineup the Diamondbacks are expecting or an out-machine that undermines the efforts of those around him? Will his six-year, $68.5 million deal prove to be a bargain or a mistake? There’s no Arizona player about whom we know less, and this one is going to be hitting in the heart of their order, at least to start the year.

Number To Know: .298

That’s Trumbo’s career on-base percentage. He's one of just eight active players with an OBP below .300 in 2,000 or more plate appearances, and his is sixth-worst on that list. Of the five men below him, two are defense-first catchers (Jeff Mathis and Jose Molina) and the other three are slick-fielding utility infielders (Clint Barmes, Darwin Barney and Brendan Ryan). All five, with the possible exception of Barmes, are closer to washing out of baseball than ascending to a full-time job, largely because of the frequency with which they make outs at the plate. Trumbo did have a .317 OBP in his All-Star season of 2012, but he has failed to reach even .295 in any of his other major league campaigns.

Scout's Takes

Most Overrated: Aaron Hill

“They thought they were going to get more production out of him. To me, it’s probably just age catching up with him. He doesn’t move as well defensively. He doesn’t run as well. He’s maybe lost a little bat-speed. There’s not much left from what I see. He’s going to cheat and run into a few balls and hit you some doubles, but I don’t see where he adds a lot compared to anyone else.”

Most Underrated: David Peralta

“I don’t think he was on anyone’s radar when he got called to the big leagues last year, and he’s a guy that’s got a chance to grow into a regular. Peralta is an interesting story, a converted pitcher. I saw him in Double A last year in Mobile, and he keeps growing on you. He’s a guy that can play both corners. He’s a grinder. He hangs in okay versus lefthanded pitching. He has a gap-to-gap approach. He’s got enough power in there. If he’s not a soft-regular–type guy, then he’s a quality fourth outfielder, I think.”